Years ago, a friend of mine and his buddy were traveling around Japan by rail. They figured out real quick what we all know: Japanese restaurants are expensive. So they got smart and started watching where the construction workers were eating lunch. In Kyoto, for example, they went to a blue-collar place and got huge bowls of noodles with some veggies and meat for $3-4. The rest of the day, they snacked on trail mix from their packs if they got hungry.
Normally, in most cities abroad their are people who sell things in the streets, sort of moving salespeople, often with handmade jewelry. When I was in Cusco, Peru, I was flirting with one of the girls, and I visited here at her hidden room. It was amazing to find a one dollar per night room. There were many people with rooms, but the place was way off the beaten path.